Power hammers or jack hammers having rapidly oscillating pistons or heads delivering blows to an anvil have been provided with recoil springs to dampen vibration or jumping of the hammer. These springs have been of the cylindrical helical type housed within the body of the jack hammers requiring extension of the housing and had no relationship to the hardness or impact resistance of the work being acted upon by the tool. They were relatively weak, being collapsed under appreciable downcrowding loads to present a solid column between the tool and the hammer, generating heat and a violent pogo stick action.
It would be an improvement in this art to provide anexternal, easily changed spring attachment between the jack hammer housing and the anvil impacted tool effective to maintain the tool in contact with the work and provide an operating clearance gap between the anvil and the hammer.
It would be a specific improvement in this art to provide a torsion or hairpin type spring bottomed at one end on the jack hammer housing and at the other end on the tool to accommodate a lengthy tool stroke without collapsing the spring.
It would be a still further specific improvement in this art to correlate the spring stiffness with the hardness or impact resistance of the work using weaker springs for relatively soft work usage.